1. Field of the Invention
The present invention relates to an apparatus for detecting nickel/vanadium contained in an oil. The present invention is useful in conjunction with evaluating oil to determine the existence, concentration and the like of nickel (Ni) and vanadium (V), which are heavy metals contained in oils such as crude oil and heavy oil.
2. Description of the Prior Art
Apparatus for detecting nickel/vanadium contained in an oil utilizing an atomic absorption method and a wave-length dispersion type X-ray fluorescence method have been known.
However, the former method, which utilizes an atomic absorption method, has a disadvantage in that a remarkably troublesome and time consuming pretreatment of the oil to be measured is necessary. This treatment involves heating the oil to be measured together with concentrated sulfuric acid until it is carbonized and then heat treating the resultant product at 575.degree. C. under a dry atmosphere to turn it into an ash which is subsequently dissolved in a reagent. That is to say, for example, if the quantity of oil to be treated is 20 g, it takes 20 hours for heating/carbonizing and one night for turning the resultant product into an ash under a dry atmosphere. Also, in the heating/carbonizing operation, a subtle control of the heating temperature and agitation of the mixture are always required in order to prevent an abrupt boiling of the mixture from occurring.
Also, the latter method, which utilizes a wave-length dispersion type X-ray fluorescence method, has a disadvantage in that it is necessary to sufficiently increase the distance of an X-ray fluorescence-measuring path from a sample cell, in which the oil to be measured is housed, to a wave-length dispersion type X-ray fluorescence detector. As a result, the measuring path must be adapted to be maintained under a vacuum atmosphere so that fluorescent X-rays may not be absorbed and attenuated in the long measuring path and consequently, steps must be taken to prevent the dispersion due to boiling of the oil sample in a vacuum atmosphere. Such steps necessitate a remarkably troublesome and time consuming pretreatment of the oil to be measured, such as a treatment for turning the oil into an ash sample as well as melting and glassification of each sample. The pretreatment steps are similar to those used in the apparatus utilizing an atomic absorption method and the apparatus as a whole is large-sized and complicated.